5 Organics on the Rocks: A Cosmic Origin for the Seeds of Life
33
5.4 Where Do We Go from Here?
A common perception of the chemistry in space environments is the tendency toward
uncontrollable reaction pathways that produce complex mixtures containing fundamental prebiotic building blocks and a plethora of undesirable and intractable products. The fact that a number of molecular components of contemporary organisms
can be produced in the laboratory does not necessarily mean that they were essential
for the origin of life, or that they were prebiotically available. In space there are
many mechanisms by which biochemically interesting species can be synthesized.
Not all pathways are equally efficient, but the broad range of conditions under which
organic compounds form demonstrates that their synthesis can occur in a wide variety of astronomical regions. We do not have a coherent scenario for the origins of
life on Earth. What we do know is that many organic compounds, including several
of those crucial to the functioning of modern organisms, are routinely produced by
cosmic chemistry, and are likely widespread throughout the Universe. What remains
problematic is the understanding of how such chemical entities may have spontaneously organized in systems that can self-assemble, process information, orchestrate
reaction pathways, and ultimately self-replicate.
If the starting point for our story is straightforward, the subsequent steps are
uncertain, made up of things we know and understand with speculations founded on
intuition, together with some ideas based on imagination rather than science. It’s a
complicated situation, but our journey in search of the lost roots of life has certainly
begun, is clearly heading in the right direction, and is still in progress.
References
1. T.S. Boyajian, D.M. LaCourse, S.A. Rappaport, et al., Planet Hunters IX. KIC 8462852—
where’s the flux? MNRAS 4, 3988–4004 (2016). https://doi.org/10.1093/mnras/stw218
2. F.J. Dyson, Search for artificial stellar sources of infrared radiation. Science 131, 1667–1668
(1960). https://doi.org/10.1126/science.131.3414.1667
3. P. Woods, Melting moons make Tabby’s star murky. Nat. Astron. 3, 961–961 (2019). https://
doi.org/10.1038/s41550-019-0946-1
4. B.A. McGuire, 2018 census of interstellar, circumstellar, extragalactic, protoplanetary disk, and
exoplanetary molecules. ApJ Supp. Ser. 239, 17 (2018). https://doi.org/10.3847/1538-4365/
aae5d2
5. A.C. Cheung, D.M. Rank, C.H. Townes, D.D. Thornton, W.J. Welch, Detection of water in
interstellar regions by its microwave radiation. Nature 221, 626–628 (1969). https://doi.org/
10.1038/221626a0
6. F.C. Gillett, W.J. Forrest, Spectra of the Becklin-Neugebauer point source and the KleinmannLow nebula from 2.8 to 13.5 microns. ApJ 179, 483 (1973). https://doi.org/10.1086/151888
7. R.T. Garrod, E. Herbst, Formation of methyl formate and other organic species in the warm-up
phase of hot molecular cores. A&A 457, 927–936 (2006). https://doi.org/10.1051/0004-6361:
20065560
8. C. Cecchi-Pestellini, S. Aiello, Cosmic ray induced photons in dense interstellar clouds.
MNRAS 258, 125–133 (1992). https://doi.org/10.1093/mnras/258.1.125
9. A. Legér, M. Jura, A. Omont, Desorption from interstellar grains. A&A 144, 147–160 (1985)
33
5.4 Where Do We Go from Here?
A common perception of the chemistry in space environments is the tendency toward
uncontrollable reaction pathways that produce complex mixtures containing fundamental prebiotic building blocks and a plethora of undesirable and intractable products. The fact that a number of molecular components of contemporary organisms
can be produced in the laboratory does not necessarily mean that they were essential
for the origin of life, or that they were prebiotically available. In space there are
many mechanisms by which biochemically interesting species can be synthesized.
Not all pathways are equally efficient, but the broad range of conditions under which
organic compounds form demonstrates that their synthesis can occur in a wide variety of astronomical regions. We do not have a coherent scenario for the origins of
life on Earth. What we do know is that many organic compounds, including several
of those crucial to the functioning of modern organisms, are routinely produced by
cosmic chemistry, and are likely widespread throughout the Universe. What remains
problematic is the understanding of how such chemical entities may have spontaneously organized in systems that can self-assemble, process information, orchestrate
reaction pathways, and ultimately self-replicate.
If the starting point for our story is straightforward, the subsequent steps are
uncertain, made up of things we know and understand with speculations founded on
intuition, together with some ideas based on imagination rather than science. It’s a
complicated situation, but our journey in search of the lost roots of life has certainly
begun, is clearly heading in the right direction, and is still in progress.
References
1. T.S. Boyajian, D.M. LaCourse, S.A. Rappaport, et al., Planet Hunters IX. KIC 8462852—
where’s the flux? MNRAS 4, 3988–4004 (2016). https://doi.org/10.1093/mnras/stw218
2. F.J. Dyson, Search for artificial stellar sources of infrared radiation. Science 131, 1667–1668
(1960). https://doi.org/10.1126/science.131.3414.1667
3. P. Woods, Melting moons make Tabby’s star murky. Nat. Astron. 3, 961–961 (2019). https://
doi.org/10.1038/s41550-019-0946-1
4. B.A. McGuire, 2018 census of interstellar, circumstellar, extragalactic, protoplanetary disk, and
exoplanetary molecules. ApJ Supp. Ser. 239, 17 (2018). https://doi.org/10.3847/1538-4365/
aae5d2
5. A.C. Cheung, D.M. Rank, C.H. Townes, D.D. Thornton, W.J. Welch, Detection of water in
interstellar regions by its microwave radiation. Nature 221, 626–628 (1969). https://doi.org/
10.1038/221626a0
6. F.C. Gillett, W.J. Forrest, Spectra of the Becklin-Neugebauer point source and the KleinmannLow nebula from 2.8 to 13.5 microns. ApJ 179, 483 (1973). https://doi.org/10.1086/151888
7. R.T. Garrod, E. Herbst, Formation of methyl formate and other organic species in the warm-up
phase of hot molecular cores. A&A 457, 927–936 (2006). https://doi.org/10.1051/0004-6361:
20065560
8. C. Cecchi-Pestellini, S. Aiello, Cosmic ray induced photons in dense interstellar clouds.
MNRAS 258, 125–133 (1992). https://doi.org/10.1093/mnras/258.1.125
9. A. Legér, M. Jura, A. Omont, Desorption from interstellar grains. A&A 144, 147–160 (1985)